I've tagged this book as science fiction, because it contains science-fiction elements. It has been in the Library fro some years, but this is an improved edition, and with the original cover. I downloaded it thinking it was an Arsene Lupin book, due to the familiar image of Lupin on the supplied cover. Not so.
Strange projections of images are seen, baffling the inhabitants of Meudon. The explanations, and the nature of the images, baffle all, although there is some suggestion that they originate from Venus.